@moorereason’s solution is awesome if you find yourself using a lot of page-level scripts, but to further the point made w/r/t separation of concerns if you’re talking about more than one page using a script not necessarily used by the entire site, you can also use block in your layouts…
So, baseof.html…
<!--All the other stuff in you base template-->
<!-- Somewhere around your footer -->
...
<script src="/js/scrip-that-runs-everywhere"></script>
{{block "addscripts" . }}
{{end}}
Then in your layout for that page (or series of pages…):
...
{{define "addscripts"}}
<script src="/scripts/script-only-for-this-type-of-layout.js"></script>
{{end}}
This keeps you from having to muddy metadata (arguably part of content as well) with your presentation and behavior. That said, it’s less on-the-fly flexible as the solution put together by @moorereason. You could also use a series of partials and then pipe the appropriate partial into the newly defined block or just add the partial to the layout.
That said, if you are really nutso about performance and reducing HTTP requests, using a build tool to uglify and minify, and fiddling with cache-control, you may want to add the additional js to a single final concatenated js, use a try and catch or check for a value, etc…but this is all you in terms of the type of content you’re serving up and the anticipated behavior of your users.